Side Slip (wing down/cross control) Landing Technique on Airbus (A330)

[Goldenrivett]

villas,
In post #35 you said

Airbus does not recommend it and the reason is stick out of neutral is rate of roll demand.

All I'm asking is why you think you'd need stick out of neutral to maintain bank / wings level with side slip and why you think the rudder loads with constant side slip is enough to break it - yet it must be designed to withstand rudder loads with EFTO.

Till the A300 crashed in New York they didn't know that overuse of rudder can cause the tail to brake off did they?

You don't seem to be very confident in the loads the Airbus fin can withstand under constant rudder deflection. How will you cope with your EFTO?

Can you side slip an airliner to lose height like a small trainer?

Suggest you read The Gimli Glider ? Damn Interesting
If the options are to do a forced landing beyond half way down a short runway, or loose some more energy on short finals - then I might try side slipping. In normal ops, side slipping is simply inefficient flight.

[TyroPicard]

titaniumwings

As you said because there is no input in the side stick there should be no bank

That is not what I said! Excuse me for shouting, but Airbus FBW in roll WILL NOT MAINTAIN CONSTANT BANK ANGLE. Stick free it tries to maintain zero roll rate, but if the bank angle is changed by turbulence or rudder input it will try to stop the roll, but IT WILL NOT RETURN TO THE ORIGINAL BANK ANGLE.
Is that clear enough?

[titaniumwings]

TP- bear with me for a while. I m not trying to be funny but let me try this one more time. Say do a right turn then neutralise the side stick at 5deg right bank. Then put in left rudder input gradually gently. What will the bank angle then be?

Thanks.

[FlightDetent]

I'll try: the bank angle will be whatever the presumed rudder input will create. Large possibilities available with swept wing.

No lateral SS input, no roll demand. Unless, of course, you can take her beyond 33 degs.

[ACMS]

Vilas----ok good after you re read my post above

Gentle controlled smooth sideslips ( partial rudder applied ) at low speeds are not going to knock the tail off, the AA A300 in JFK was sudden full rudder control that placed rapid excessive sudden loads on the fin.

Anyway blue skies...

[hikoushi]

"And I have to disagree with hikoushi about manual thrust in gusty wind. It is exactly opposite of what Airbus recommends. You don't knock out GS Mini and convert AB FBW to Boeing it is not a safe way to fly. It is safer to change your company and fly a Boeing instead."

vilas, methinks you are trying to say that either the Airbus or the Boeing aircraft line is safer than the other, but I can't quite tell which one. Either way, horse-pucky.

I see according to your profile that you are a sim instructor on the 320, but have not flown the 330. In the training world it is easy to lose touch with real flying, yes? Remember the Airbus Golden Rule that it "...can be flown like any other aircraft"? The rule at the very front of "The Book"? Yes A/THR is the way to go most of the time; the FBW is designed to work with it and it all does a very good job. However, the 330 has very smooth and responsive throttles and is a joy to truly hand-fly as well.

GS mini is done doing it's "thing" as you descend through 400 feet. It does a great job of keeping an energy reserve and preventing excessive thrust changes. Below 400 feet, the GS mini function blends out. Your target speed becomes your Vapp, and with shear and gusts (big ones) it is common to have that speed drop to Vls and a great big burst of power come in, suddenly and without warning, slightly out-of-phase from the wind. Think back to your 747 days and all the inertia of a big heavy airplane, then couple it with the Airbus FBW and autothrust. This is where a steady manual thrust setting can be more comfortable IF you are comfortable, proficient, and current at actually using it. Barring the wild winds we are talking about here, the A/THR GENERALLY stays ahead of the speed very well AS LONG AS you have good pitch control (and incidentally if you have trouble keeping the nose pointing straight on a single-engine ILS in the simulator using autothrust, I guarantee you your pitch control is junk).

Do you fly the 330? If so, do you fly frequently enough into gusty winds to have become comfortable with them IN THE 330? Do you fly, and have you used, manual thrust enough to be as comfortable with it as with the autos? If not, does your company allow the A/THR to be deferred or MEL'd? Ours does. If yours does too, and your SOP allows it, I HIGHLY recommend you learn how to fly the airplane "like any other aircraft". You state that (paraphrasing) turning the autothrust off is "not a safe way to fly"; I sincerely hope you do not wind up getting an aircraft with the autothrust deferred and having to figure it out for the first time under pressure. Practice and be comfortable flying your aircraft at ALL levels of automation, as there are times where you will NEED all of them. And if your SOP allows it (ours does), there are times where you may WANT to have a little bit bigger of a bag of tricks to choose from that are all equally comfortable and safe, no matter what aircraft you fly.

Tailwinds to you and good luck out there.

[stilton]

'Below 400 feet, the GS mini function blends out. Your target speed becomes your Vapp, and with shear and gusts (big ones) it is common to have that speed drop to Vls and a great big burst of power come in, suddenly and without warning, slightly out-of-phase from the wind'



No thanks, i'll stick with manual thrust on my Boeing

[vilas]

Hikoushi
I was not talking about individual flying ability or developing the skill to fly without auto thrust. You must acquire all the skills that it takes. I didn't fly 330 but I did A320. But starting from B707 to non FBW airbuses and classic 747, without the luxury of PFD and trend arrow I have enough in the kitty to handle well anything that others can do. I found A320 the easiest aeroplane to handle with or without any automation whatsoever. We didn't use GS mini in 747 but speed addition which was bled off at flare but GS mini is a good concept. Can pitch control be easier than airbus normal law? In a GA with TOGA power you need to pull up otherwise it gets damped. So in approach and landing a burst of power is not a big deal. You just point the bus like a gun at the threshold let the thrust do what it will. If you have good scan you will have good control.

[vilas]

stilton
If you were to fly an Airbus you will be amazed how easy it is compared to 737. That is the problem with AB FBW it takes some of the glamour away because even a well trained inexperienced co-pilot flies it equally well.

[pontifex]

Vilas

I agree 110%. I have flown both AB and B (and McDD, DH, Lockheed and Fokker). The A320 was without doubt the sweetest to handle. Equalled only by Vickers.

[hikoushi]

As much as people (who have never flown one) slam the Airbus philosophy, I must admit I have really learned to enjoy it, even with all it's quirks. It will never have the visceral feel of an older Boeing or Douglas (or Piper for that matter), but it is definitely a pleasure to fly. I still encounter Airbus pilots in all seats who never developed comfort flying the airplane and leave the autos on absolutely all the time. All of them wish they were flying a 777 instead. If they would just take the time to fly the airplane for what it IS, they would find the Zen in the Art of Bus Driving (or just bid back over to the Boeing fleet).

But you know what happens when you go back and fly long-haul in a Boeing after being on the Bus for a few years? YOU CAN'T STAND IT. IT IS PHYSICALLY UNBEARABLE to have that damned control column jamming your legs again. You never noticed it before, but after experiencing that legroom, you now start thinking about deep-vein thrombosis. You leave the autopilot on all the time anyway so you don't care that the airplane "feels" better, you just care about that damn column. And the table! Where is my meal tray going to go? And my coffee? Come on, my break doesn't start until 0900 and it's only 0300! We have a 14 hour block to ZBAA today, this thing is uncomfortable as all getout! Give me back my French ergonomics!!

Time to call it a day and go have a beer. What whining little snots we become with a little comfort!

[RetiredBA/BY]

Quote: I trained in Canada where they taught the wing down technique. When I got back to the UK I was made to use the crab technique by RAF QFIs. I continued with the latter until I got to ETPS and subsequently onto B Sqn at A&AEE. During my time there I did a considerable amount of work on landing techniques where I was given carte blanche to try what I liked. My findings were conclusive - wing down is far superior. OK, so you land on one wheel, but you are still, in fact, still partially wing bourne at this time. Advantages are as follows: the fine judgement on when to kick off drift is very difficult to get right and, if you don't, the ac will land with crab on which can significantly stress some ac. In strong, gusty X winds, with wing down, you land with the control deflections which are exactly what you want for the roll out which prevents the arm and leg blurr that usually follows a crab touch down. It is easy to land without drift because the instant of touchdown is not critical and so is a much smoother. I have used this technique with ac ranging fom Slingsby T67s through to VC10s taking Comet and Lancaster en route. The only ac not suitable for this treatment are things like 747s A340 and B52. Incidentally, I have fair experience on both A320 and B737. There is no mystery - they both handle like normal ac. In fact I found the A320 a little nicer to handle manually than its rival. (Retire to WWll bunker at the end of my garden). As you may appreciate this is a big hobby-horse for me, but I do wish the RAF had been broad minded enough in times past to get away from sacred cows and try different techniques. Unquote.



As an ex RAF standards QFI, and later Boeing TC (with time on the VC10 too) I can assure you the RAF teaches the crab technique because it works so very well on all types (although I have no Airbus experience) and on podded aircraft minimises the chance of pod strike. Why change a perfectly good technique and on my Boeing conversion at Seattle, it was a fully approved technique. The thought of significant bank near the runway with a CF6 hanging under the wing fills me with dread, as does the thought of landing in a 40 k crosswind without decrabbing !

In my almost 40 years of flying, RAF and civil, the ONLY time I ever saw a wingdown crosswind approach was when my Boeing was making a coupled approach.

If it ain't broke why fix it ?

[pontifex]

Hi there Retired BA/BY. I was also a standards QFI and also a commercial FI so our background is rather similar. I still maintain that, where physically feasible, the wing down is superior. I have also done instrumented trials on Xwind handling and the results were rather conclusive. The aircraft involved were Nimrod, C130 and PC9. In all cases the wing down was established by at least 100ft so the approach was stabilised in good time before touchdown.

[hikoushi]

Many years of wing-down landings in Cessnas and such. Flew GA from a young age and only went for the commercial path when it dawned on me that it is better to fly on someone else's dime.

When pursuing my instructor's certificate many moons later, a wise old eagle taught me the technique I've used since on pretty much everything. Fly the airplane in the crab INTO THE FLARE, round out and hold it just above the deck. Squeeze in the rudder to straighten the nose while simultaneously squeezing in opposite aileron to keep wings level; at the moment the nose is dead strait, keep the wing coming down slightly and continue to rudder the nose down the runway. This is, of course, EXACTLY the same technique you would use to establish your "wing-down sideslip" at 100 feet or wherever.

BUT, since you are right over the runway, your slip is interrupted by the upwind wheel pressing into the ground. It will do so with just the scarcest bit of bank, since you are "pirouetting" in the flare. Also lets you choose the moment the wheel touches, in a similar way to a wheel landing in a taildragger. And, if you blow it and flare high, you just wind up in a normal wing-down approach. In a big plane usually not even that happens, as your inertia will keep you tracking straight a good bit longer than in a lightplane (mega-winds notwithstanding).

In the Airbus I do what basically feels just like that method. Starting it right around the first "retard" call along with the final throttle reduction seems like a decent starting target, then adjust that for energy state, wind, steeper approach slope, etc.

This is of course, just a technique so take it or leave it.

So far so good, except for the first few mega-pancakes and the occasional random wonky approach (usually after a long red-eye that lands before sunrise. Good morning EARTH! "No, Tower, we don't need the trucks! I was just using the main landing gear to drill for oil here on the numbers of 23 Left! What's that? No, we didn't strike crude, that is just my number 2 tire vaporizing").

[glendalegoon]

hikoushi


a lovely way of saying it. most planes will do just fine with the crab and decrab very close to the runway, over the runway, at very , very low altitude (way under 50')

I understand why so many like the wing down method. It means they are lacking in skill, technique, and the courage to take the plane down close to the ground and do many things at once.

kick rudder

lower wing

bring nose up

and all this done at the same time or nearly so. sort of hard like walking and chewing gum at the same time.

And while we are at it, you can even use assymetrical thrust to help you along. Many will doubt this, but it is usually a lack of skill which could be developed if you like. Try it in the sim on a non jeopardy ride.

There are pilots that get by and then there are pilots that are fully in command of an aircraft.

choose the type of pilot YOU want to be.

[bubbers44]

One night I was on my first captain flight with an FO on his first Lear flight landing in a 30 knot direct crosswind. He asked how does this thing land in a crosswind? I said "I don't know, never have."

I used Glendalegoon's method including leaving the upwind engine power up some and got a great landing. It is all done at once late in the flare and is not difficult in any airplane.

[ACMS]

So did the paying punters down the back know how incompetent you were?

Surely you were "trained" in an approved FFS or if that wasn't available an Aircraft? And had completed crosswind landings with an instructor Pilot along BEFORE being cut lose in a fast swept wing Jet??????!

I don't know anyone that would suggest using differential thrust ( especially in a centerline thrust type A/C like a Lear Jet where it would be basically useless ) to get the Aircraft straight in the Flare.

THAT'S WHAT THE RUDDER IS FOR, and if it's not effective enough I would suggest the crosswind is a little excessive

[Capn Bloggs]

Originally Posted by ACMS

I don't know anyone that would suggest using differential thrust ( especially in a centerline thrust type A/C like a Lear Jet where it would be basically useless )

Arr ,yes, the old "engines are on the body, no assy thrust there" furphy. Ever flown a Lear, ACMS?

[vilas]

I have never understood the need to develop non standard procedures. Using differential thrust for crosswind landing is absolutely non standard procedure. No manufacturer needed it for certification nor has recommended it. On AB FBW if you forget to bring that thrust levers to idle the ground spoilers will not deploy so no auto brakes. Landing on short slippery runway not a smart thing to do.

[pontifex]

Glendalegoon

There is no doubt that the "kick off drift" technique requires more skill to produce an acceptable landing. This, of course, means that its success rate is inevitably less than wing down. As a result the aircraft is more stressed and the pax less happy. You seem to imply that, because you are an above average pilot, you would deny lesser mortals the opportunity to produce consistent, acceptable results. "Standing up in a hammock" springs to mind.